A standard hand drill has a housing from which extends a drill spindle centered on and rotatable about an axis and having a front externally threaded end. A chuck for such a drill has a chuck element centered on the axis and formed with a forwardly open tool hole and with a threaded bore complimentarily engaging the spindle end. An adjustment element is rotatable about the axis on the chuck element and one of the elements is formed with a plurality of angled guide passages and the other element is formed with a screwthread centered on the axis. Respective jaws in the passages exposed in the tool hole each have a toothed edge meshing with the other-element screwthread so that relative rotation of the elements displaces the jaws along the respective passages. In a self-tightening chuck the screw-thread is typically formed on the chuck element or body and the passages in the rotatable adjustment element, but in a standard chuck not set up for self tightening the screwthread is on a ring forming the adjustment element and the guide passages are formed right in the chuck body.
Normally the chuck and the body of the drill are made by different manufacturers. Thus the spindle is of standardized construction, that is of a predetermined diameter and thread size, so that it can be fitted to a chuck that is similarly of standardized construction, at least with regard to the formations coupling it to the drill spindle. As a result the finished drill often has the look of something assembled out of different components in that the chuck is clearly just fitted on the end of the drill body.